scholarly journals Astray State-Laminar Forced Convective Heat Transfer of Al2O3 – H2O Nanofluid through 3D-Rectangular Cross- Sectional Duct

2019 ◽  
Vol 8 (2S3) ◽  
pp. 899-907
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Convective Heat Transfer ◽  
Friction Factor ◽  
Convective Heat ◽  
Flow Rate ◽  
Base Fluid ◽  
Volume Fraction ◽  
Phase Model ◽  
Forced Convective Heat Transfer

A Steady state-laminar forced convective heat transfer has been simulated by Computational Fluid Dynamics (CFD) with a Single Phase Model (SPM), Multi Phase model & Diameter effects and also determined the effects of nanoparticles concentration and nanofluid flow rate through 3D rectangular duct under certain boundary condition (constant heat flux). The nanofluid contains Alumina nanoparticles of size 60nm diameter used for MPM which is mixed with base fluid (water) with volume fraction of 0% ≤ ȼ ≤ 5% and Reynolds number (Re) ranges from 250 ≤ Re ≤ 1000. ANSYS 18.0 has been used for simulation. Three cases of analysis have been carried out in which the thermal conductivity (k) and dynamic viscosity (µ) of nanofluids are determined using two sets of theoretical models and one set of experimental k & µ data from literature respectively. The nanoparticles which stay more dispersed in the base fluid due to increase in Reynolds number which improves HTC and also decreases the friction factor accordingly. Particular attention has been paid to the variation of heat transfer characteristics when the modeling approach is switched from SPM to MPM. It is revealed that higher heat transfer rates are observed in MPM. The results shows that the friction factor decreases and Nusselt number (Nu) increases when there is an increase in the flow rate and also increase in the volume concentration of the nanofluid, while the pressure drop increases only slightly. The increase in HTC is one of the most important aims for industry and researchers.

Improved Modeling of Turbulent Forced Convective Heat Transfer in Straight Ducts

1999 ◽  
Vol 121 (3) ◽  
pp. 712-719 ◽  
Author(s):  
M. Rokni ◽  
B. Sunden
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Low Reynolds Number ◽  
Eddy Diffusivity ◽  
Numerical Approach ◽  
Generalized Gradient ◽  
Forced Convective Heat Transfer ◽  
Low Reynolds

This investigation concerns numerical calculation of turbulent forced convective heat transfer and fluid flow in their fully developed state at low Reynolds number. The authors have developed a low Reynolds number version of the nonlinear k-ε model combined with the heat flux models of simple eddy diffusivity (SED), low Reynolds number version of generalized gradient diffusion hypothesis (GGDH), and wealth ∝ earning × time (WET) in general three-dimensional geometries. The numerical approach is based on the finite volume technique with a nonstaggered grid arrangement and the SIMPLEC algorithm. Results have been obtained with the nonlinear k-ε model, combined with the Lam-Bremhorst and the Abe-Kondoh-Nagano damping functions for low Reynolds numbers.

scholarly journals CONVECTIVE HEAT TRANSFER AND POWER SAVING APPLICATION OF SI BASED NANOPARTICLES IN A CIRCULAR PIPE

2020 ◽  
Vol 50 (4) ◽  
pp. 321-327
Author(s):  
Md Insiat Islam Rabby ◽  
Farzad Hossain ◽  
S.A.M. Shafwat Amin ◽  
Tazeen Afrin Mumu ◽  
MD Ashraf Hossain Bhuiyan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Base Fluid ◽  
Volume Fraction ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Circular Pipe ◽  
Working Fluid ◽  
Pumping Power

A numerical study of laminar forced convection heat transfer for the fully developed region inside a circular pipe filled with Si based nanoparticle is presented for investigating the parameters of heat transfer. Four Si based nanoparticles Si, SiC, SiO2, Si3N4 with 1-5% volume fraction have been mixed with water to prepare nanofluids which is used for working fluid to flow over a circular pipe with 5mm diameter and 700mm length. Heat transfer characteristics and pumping power have been calculated at fully developed region with constant heat flux condition on pipe wall to identify the heat transfer enhancement ratio and pumping power reduction ratio among base fluid water and each nanofluids. It is worth mentioning that utilizing SiC nanoparticle shows not only the highest increment of Nusselt number and convective heat transfer coefficient but also the highest decrement of pumping power requirement and FOM in comparison to the base fluid.

scholarly journals Intensified Thermal Conductivity and Convective Heat Transfer of Ultrasonically Prepared CuO–Polyaniline Nanocomposite Based Nanofluids in Helical Coil Heat Exchanger

2019 ◽  
Vol 64 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Abhishek Lanjewar ◽  
Bharat Bhanvase ◽  
Divya Barai ◽  
Shivani Chawhan ◽  
Shirish Sonawane
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Base Fluid ◽  
Cuo Nanoparticles ◽  
The Heat Transfer Coefficient

In this study, investigation of convective heat transfer enhancement with the use of CuO–Polyaniline (CuO–PANI) nanocomposite basednanofluid inside vertical helically coiled tube heat exchanger was carried out experimentally. In these experiments, the effects of different parameters such as Reynolds number and volume % of CuO–PANI nanocomposite in nanofluid on the heat transfer coefficient of base fluid have been studied. In order to study the effect of CuO–PANI nanocomposite based nanofluid on heat transfer, CuO nanoparticles loaded in PANI were synthesized in the presence of ultrasound assisted environment at different loading concentration of CuO nanoparticles (1, 3 and 5 wt.%). Then the nanofluids were prepared at different concentrations of CuO–PANI nanocomposite using water as a base fluid. The 1 wt.% CuO–PANI nanocomposite was selected for the heat transfer study for nanofluid concentration in the range of 0.05 to 0.3 volume % and Reynolds number range of was 1080 to 2160 (±5). Around 37 % enhancement in the heat transfer coefficient was observed for 0.2 volume % of 1 wt.% CuO–PANI nanocomposite in the base fluid. In addition, significant enhancement in the heat transfer coefficient was observed with an increase in the Reynolds number and percentage loading of CuO nanoparticle in Polyaniline (PANI).

An experimental investigation in forced convective heat transfer and friction factor of air flow over aligned round and flattened tube banks

2019 ◽  
Vol 48 (6) ◽  
pp. 2350-2369 ◽  
Author(s):  
Ataalah Hussain Jassim ◽  
Tahseen Ahmad Tahseen ◽  
Ahmed Waheed Mustafa ◽  
Md Mustafizur Rahman ◽  
Mahadzir Ishak
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Convective Heat Transfer ◽  
Friction Factor ◽  
Convective Heat ◽  
Air Flow ◽  
Forced Convective Heat Transfer ◽  
Tube Banks

Heat Transfer Characteristics of an Array of Impinging Gaseous Slot Jets

2011 ◽  
Vol 396-398 ◽  
pp. 2234-2239
Author(s):  
Zu Ling Liu ◽  
Cheng Bo Wu ◽  
Xian Jun Wang ◽  
Zheng Rong Zhang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Nozzle Exit ◽  
Convective Heat Transfer Coefficient ◽  
Heat Transfer Characteristics ◽  
Forced Convective Heat Transfer

A comprehensive experiment was conducted for heat transfer characteristics for an array of impinging gaseous slot jets to a flat plate with strong turbulence (nozzle exit Reynolds number Re=22500~64700).Find that turbulence intensity of flow has an important influence on local forced convective heat transfer coefficient. Meanwhile, the nozzle-to-plate spacing and nozzle exit Reynolds number Re would affect the mean forced convective heat transfer coefficient of the slot jets. And heat transfer efficiency of slot jets has been set to show the relation between ability of the jets and energy consumption of gas supply.

scholarly journals Enhancement of Turbulent Convective Heat Transfer using a Microparticle Multiphase Flow

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1282
Author(s):  
Tao Wang ◽  
Zengliang Gao ◽  
Weiya Jin
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Reynolds Number ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Performance ◽  
Volume Fraction ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Better Than

The turbulent heat transfer enhancement of microfluid as a heat transfer medium in a tube was investigated. Within the Reynolds number ranging from 7000 to 23,000, heat transfer, friction loss and thermal performance characteristics of graphite, Al2O3 and CuO microfluid with the particle volume fraction of 0.25%–1.0% and particle size of 5 μm have been respectively tested. The results showed that the thermal performance of microfluids was better than water. In addition, the graphite microfluid had the best turbulent convective heat transfer effect among several microfluids. To further investigate the effect of graphite particle size on thermal performance, the heat transfer characteristics of the graphite microfluid with the size of 1 μm was also tested. The results showed that the thermal performance of the particle size of 1 μm was better than that of 5 μm. Within the investigated range, the maximum value of the thermal performance of graphite microfluid was found at a 1.0% volume fraction, a Reynolds number around 7500 and a size of 1 μm. In addition, the simulation results showed that the increase of equivalent thermal conductivity of the microfluid and the turbulent kinetic energy near the tube wall, by adding the microparticles, caused the enhancement of heat transfer; therefore, the microfluid can be potentially used to enhance turbulent convective heat transfer.

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